TL;DR: Hyperbaric oxygen therapy is not a Health Canada-recognised indication for Lyme disease or post-treatment Lyme disease syndrome. Evidence tier: D (case reports and narrative reviews only). The published evidence base consists of small case reports and narrative reviews. No randomised controlled trials exist. Researchers studying HBOT for Lyme should treat current data as hypothesis-generating, not confirmatory, and weigh significant methodological gaps before drawing clinical conclusions.
What does the evidence say about HBOT for Lyme disease?
Hyperbaric oxygen therapy (HBOT) is a medical treatment that delivers 100 percent oxygen at pressures greater than one atmosphere absolute. For Lyme disease, the published literature is sparse, dated, and methodologically limited. A PubMed search for “hyperbaric oxygen therapy” combined with “Lyme disease” returns fewer than ten indexed articles as of May 2026, the majority of which are case reports, narrative reviews, or commentary pieces. No randomised controlled trials have been completed in this population.
This evidence summary is intended for researchers, clinical investigators, and academic clinicians evaluating whether HBOT for Lyme disease warrants further study. It does not constitute a clinical recommendation. Canada Hyperbarics maintains a database of more than 14,000 indexed HBOT studies, and the Lyme disease subset highlights both the limited science and the persistent patient demand for adjunctive treatment options.
Why is the chronic Lyme disease research landscape so challenging?
The category of “chronic Lyme disease” (CLD) is itself contested. The Infectious Diseases Society of America (IDSA) and the International Lyme and Associated Diseases Society (ILADS) hold differing positions on whether persistent Borrelia burgdorferi infection accounts for ongoing symptoms after standard antibiotic therapy. The Centers for Disease Control and Prevention recognises “post-treatment Lyme disease syndrome” (PTLDS), defined as objective symptoms persisting more than six months after recommended antibiotic treatment of confirmed Lyme disease.
This taxonomic disagreement complicates clinical research. Studies that enroll heterogeneous populations under the broad label of “chronic Lyme” risk pooling patients with confirmed PTLDS, patients with untreated active infection, and patients whose symptoms may have other underlying causes. A 2006 review by Stricker and colleagues in Chemotherapy emphasised that the absence of a reliable therapeutic endpoint and the presence of tick-borne coinfections create significant barriers to evaluating any adjunctive therapy, including HBOT (Stricker 2006, internal summary).
What is the mechanistic rationale for HBOT in Lyme disease?
The theoretical basis for investigating HBOT in Lyme disease centres on the oxygen sensitivity of Borrelia burgdorferi, the spirochete that causes the illness. B. burgdorferi is a microaerophilic organism, meaning it grows preferentially in low-oxygen environments. Bench studies dating back to the 1990s suggested that exposure to elevated oxygen partial pressures could inhibit spirochete proliferation in vitro.
Beyond direct antimicrobial effects, three additional mechanisms are sometimes cited in HBOT-Lyme research proposals:
- Tissue oxygenation in poorly perfused sites. Lyme spirochetes can localise to joints, connective tissue, and the central nervous system. Hyperbaric pressurisation increases plasma-dissolved oxygen, theoretically improving delivery to hypoxic foci.
- Modulation of host immune response. HBOT has documented effects on neutrophil function, cytokine expression, and oxidative-stress signalling, which could influence host-pathogen interactions.
- Anti-inflammatory effects on neuroinflammation. Some PTLDS hypotheses implicate persistent low-grade neuroinflammation, and HBOT has been studied in other neuroinflammatory conditions.
None of these mechanisms have been validated in clinical Lyme populations. The mechanistic rationale, while biologically plausible, remains hypothesis-level and has not progressed to confirmed clinical efficacy through controlled trials.
What does the case report literature show?
The most-cited HBOT-for-Lyme case report in the modern indexed literature is Huang and colleagues (2014, Journal of the Chinese Medical Association), describing a single patient with chronic Lyme disease who reported symptom improvement after adjunctive HBOT (Huang 2014, internal summary). The authors used a treatment protocol of 100 percent oxygen at 2.5 atmospheres absolute, with sessions lasting approximately 90 minutes. The patient was treated daily for a defined course.
This report illustrates the classic limitations of single-patient evidence: no comparator, no blinding, no objective outcome measurement against a control group, and high risk of confounding from concurrent antibiotic therapy. A second case report by Espiney Amaro and colleagues (2015, Journal of Laryngology and Otology) described complete recovery in a patient who presented with Lyme-associated sudden sensorineural hearing loss after combined HBOT and antibiotic therapy (Espiney Amaro 2015, internal summary). The HBOT contribution in that case is impossible to isolate from the antibiotic effect or from the natural history of acute Lyme-related labyrinthitis.
Why do review articles flag HBOT for Lyme as an unproven adjunct?
A 2005 review by Taylor and Simpson in the Journal of Chemotherapy identified HBOT as an adjunct therapy that has been used in Lyme borreliosis but explicitly noted that clinical trials had not yet been conducted (Taylor 2005, internal summary). In the two decades since that review, the situation has not materially changed. Researchers continue to identify HBOT as a candidate adjunctive therapy in narrative reviews while acknowledging the absence of controlled trial data.
A 2018 research letter in JAMA by Vox and colleagues documented online crowdfunding campaigns for HBOT in chronic Lyme disease, classifying these requests within a broader pattern of fundraising for scientifically unsupported treatments (Vox 2018, internal summary). The research letter does not adjudicate the underlying clinical question, but it does highlight the gap between patient demand for HBOT and the available evidence base. This is an important ethics-of-care consideration for Canadian researchers planning prospective studies.
How does HBOT for Lyme compare to other HBOT indications?
Comparison of evidence base across HBOT indications
| Indication | RCT evidence | Health Canada / UHMS status |
|---|---|---|
| Carbon monoxide poisoning | Multiple RCTs, systematic reviews | Recognised indication |
| Diabetic foot ulcers | Multiple RCTs, Cochrane reviews | Recognised indication |
| Sudden sensorineural hearing loss | RCTs and meta-analyses | Recognised indication |
| Delayed radiation injury | Multiple RCTs | Recognised indication |
| Long COVID | Emerging RCT data (small samples) | Investigational, not recognised |
| Lyme disease / PTLDS | None | Not a recognised indication |
The Undersea and Hyperbaric Medical Society (UHMS) maintains a list of recognised indications based on the strength of supporting evidence. Lyme disease and PTLDS are not included on the 2026 UHMS-recognised indications list. Health Canada has likewise not recognised HBOT as a treatment for Lyme disease.
What does Canadian research on Lyme disease suggest about future HBOT study design?
Lyme disease incidence has risen substantially across Canada over the past decade. The Public Health Agency of Canada reports steady increases in confirmed cases, driven by tick range expansion linked to changing climate patterns. Provinces with the highest reported incidence include Ontario, Quebec, Nova Scotia, New Brunswick, and Manitoba.
A 2024 review by Williams and colleagues in Pathogens highlighted the importance of distinguishing acute Lyme disease from PTLDS in pregnancy-related research, and emphasised the value of standard case definitions in future studies (Williams 2024 review on PubMed). The same methodological principles apply to any prospective HBOT trial. Investigators interested in pursuing a Canadian HBOT-Lyme study should consider the following design elements:
- Standardised case definition. Use the CDC PTLDS criteria or an equivalent rigorously defined population, with serological confirmation of prior B. burgdorferi infection.
- Sham-controlled randomisation. A sham hyperbaric protocol (1.2 to 1.3 atmospheres absolute on room air) is the established control for HBOT trials and protects against expectancy bias.
- Pre-specified primary endpoint. Validated patient-reported outcome measures or objective neurocognitive testing avoid the endpoint ambiguity that has plagued prior CLD research.
- Adequate sample size. Power calculations should reflect realistic effect sizes; prior PTLDS antibiotic trials have informed appropriate enrollment targets.
- Pre-registered protocol. ClinicalTrials.gov or ISRCTN registration reduces publication bias.
- Independent monitoring. Given the contested nature of the field, independent adjudication of outcomes is essential to credibility.
What are the safety considerations for HBOT in this population?
HBOT has a well-characterised safety profile in recognised indications. Common adverse events include middle ear barotrauma (the most frequent), reversible myopia, and sinus squeeze. Rare but serious risks include oxygen toxicity seizures and pulmonary oxygen toxicity. Patients with chronic neurological symptoms may warrant additional pre-treatment screening for seizure risk factors.
In Canada, HBOT delivered in hospitals and regulated facilities follows protocols aligned with UHMS guidelines and provincial regulatory oversight. Researchers planning Lyme-related HBOT studies must ensure the treating facility meets accreditation standards and that the protocol pressure and duration are documented per published trial conventions.
Frequently asked questions about HBOT and Lyme disease research
Is there any RCT-level evidence for HBOT in Lyme disease?
No. As of May 2026, no published randomised controlled trial has evaluated HBOT for Lyme disease, chronic Lyme disease, or PTLDS. The literature consists of case reports, case series, and narrative reviews.
Is HBOT a recognised indication for Lyme disease in Canada?
No. Health Canada does not approve HBOT for Lyme disease. The UHMS does not list Lyme disease among its recognised indications. Patients seeking HBOT for Lyme symptoms in Canada do so as an off-label or experimental treatment, typically at private clinics, with no provincial health insurance coverage.
What was the protocol used in published Lyme HBOT case reports?
Published case reports describe protocols ranging from 2.0 to 2.5 atmospheres absolute, with 60- to 90-minute sessions, daily for 20 to 40 sessions, often combined with concurrent antibiotic therapy. The variability across reports limits comparability.
Why has no RCT been conducted in 30 years of clinical interest?
Several factors contribute: contested case definitions for chronic Lyme, limited funding for HBOT trials outside recognised indications, methodological complexity of measuring PTLDS outcomes, and the relatively small size of the affected population willing to undergo sham-controlled HBOT protocols. The 2018 JAMA letter on crowdfunding underscores the demand-supply mismatch.
What outcome measures would be most appropriate for a future trial?
Validated PTLDS-relevant instruments include the Fatigue Severity Scale, SF-36 quality-of-life subscales, neurocognitive batteries (such as digit symbol substitution and the Wechsler Adult Intelligence Scale), and pain visual analogue scales. Inflammatory biomarkers and serial serology can serve as secondary endpoints. Pre-specification is essential.
Could HBOT interact with antibiotic therapy in Lyme treatment?
Theoretically yes, through both pharmacodynamic and host-immune pathways, but no clinical pharmacology studies have characterised this interaction in Lyme patients. Trial designs that include both arms (HBOT plus antibiotics versus antibiotics alone versus HBOT alone) would clarify additive or independent effects.
Where can researchers access the full HBOT Lyme literature?
Canada Hyperbarics indexes more than 14,000 HBOT-related studies in its public research database, with the Lyme disease subset accessible via condition filter. Each entry includes a structured summary and a direct PubMed link.
What should researchers and clinical investigators take from this review?
The published evidence base for HBOT in Lyme disease is insufficient to support efficacy claims and equally insufficient to definitively rule out a therapeutic role. The field requires a properly powered, sham-controlled, pre-registered randomised trial with a standardised PTLDS case definition before any clinical recommendation can be advanced. Canada Hyperbarics encourages Canadian investigators considering this research direction to consult the Canadian regulatory pathway resources and the UHMS for protocol guidance.
For practitioners and patients exploring HBOT options in regulated settings, the Canada Hyperbarics facilities directory lists hospitals and regulated facilities across Canadian provinces.
Reading time: 8 minutes. This research summary was prepared by the Canada Hyperbarics editorial team and references peer-reviewed studies indexed on PubMed. Published 16 May 2026.
References
Huang CY, Chen YW, Kao TH, et al. Hyperbaric oxygen therapy as an effective adjunctive treatment for chronic Lyme disease. J Chin Med Assoc. 2014;77(5):269-71. DOI: 10.1016/j.jcma.2014.02.001
Stricker RB, Lautin A, Burrascano JJ. Lyme disease: the quest for magic bullets. Chemotherapy. 2006;52(2):53-9. DOI: 10.1159/000091726
Taylor RS, Simpson IN. Review of treatment options for Lyme borreliosis. J Chemother. 2005;17 Suppl 2:3-16. DOI: 10.1179/joc.2005.17.Supplement-2.3
Espiney Amaro C, Montalvao P, Huins C, Saraiva J. Lyme disease: sudden hearing loss as the sole presentation. J Laryngol Otol. 2015;129(2):183-6. DOI: 10.1017/S0022215114003417
Vox F, Folkers KM, Turi A, Caplan AL. Medical crowdfunding for scientifically unsupported or potentially dangerous treatments. JAMA. 2018;320(16):1705-1706. DOI: 10.1001/jama.2018.10264
Williams ME, Schwartz DA, DeBiasi RL, Mulkey SB. Examining infant and child neurodevelopmental outcomes after Lyme disease during pregnancy. Pathogens. 2024;13(12):1029. DOI: 10.3390/pathogens13121029
Medical disclaimer: This content is for informational purposes only and does not constitute medical advice. HBOT for Lyme disease is not a recognised indication in Canada. Patients should consult a qualified healthcare professional before pursuing any hyperbaric oxygen therapy. Researchers and clinical investigators should consult institutional review board guidance and current regulatory requirements before designing studies in this area.